Spectroscopic performance of thick HgI/sub 2/ detectors

This paper presents the spectroscopic performance of two newly developed pixelated HgI/sub 2/ detectors. These detectors are 1/spl times/1/spl times/0.814 cm/sup 3/ and 1/spl times/1/spl times/1.016 cm/sup 3/ in size. Each detector has four closely packed 1/spl times/1 mm/sup 2/ anode pixels at the center of one of the 1/spl times/1 cm/sup 2/ surfaces. These anode pixels are surrounded by a large anode. All results presented here are based on events from a sub-volume underneath the anode pixels. In these detectors, signals were read out by a discrete electronics based on multiple A-250 pre-amplifiers and a digital oscilloscope for sampling pulse waveforms. Depth sensing technique was used to correct the depth-dependent variation in photopeak amplitude. Main results presented are: (1)energy resolutions of 0.85 /spl sim/ 1.3% have been achieved on these detectors; (2) the electron mobility-lifetime product was measured to be /spl sim/1/spl times/10/sup -2/ cm/sup 2//V and the measured electron lifetime was /spl sim/200 /spl mu/s and (3) variation in electron drifting properties under different anode pixels were observed. Significant non-uniformity in internal electric field strength was also experimentally demonstrated.